Engine governor with modifier



July 29, 1952 v c. MUZZEY ETAL 2,605,095

ENGINE GOVERNOR WITH MODIFIER Filed April 8; 1948 9 Sheets$heet 1 V I 4 INVENTORS'H July 29, 1952 c. MUzzEY ET AL 2,605,095

ENGINE GOVERNOR WITH MODIFIER Filed April s, 1948 9 Sheets-Sheet 2 INVENTORS f L M vfa V 1 15/13! 1 n I July 29, 1952 c. L. MUZZEY ET AL 2,605,095

} ENGINE GOVERNOR WITH MODIFIER Filed April 8, 1948 9 Sheetrs-Sheet 3 Q I lNVE/IEZTORi BY C. L. MUZZEY ETAL ENGINE GOVERNOR WITH MODIFIER July 29, 1952 9 Sheets-Sheet 4 Filed April 8, 1948 July 29, 1952 c. L. MUZZEY El'AL ENGINE GOVERNOR WITH MODIFIER 9 Sheets-Sheet 5 Filed April 8, 194a n 0 .Z 3 ,3 4 m 1 w ml 6 .3 w 4v a: Z z MM M 4 K u In 2 H y 1952 c. L. MUZZEY ETAL 2,605,095

ENGINE GOVERNOR WITH MODIFIER Filed April 8, 1948 9 Sheets-Sheet 6 July 29, 1952 c. L. MUZZEY ET AL 2,605,095

ENGINE GOVERNOR WITH MODIFIER Filed April 8, 194a 9 Sheets-Sheet 7 IN VEN TORS y 1952 c. 1.. MUZZEY ET AL 2,605,095

ENGINE GOVERNOR WITH MODIFIER Filed April 8. 1948 9 Sheets-Sheet a Z I INVENTORS By M fi ATToRN E July 29, 1952 c. MUZZEY ET AL 2,605,095

' ENGINE GOVERNOR WITH MODIFIER Filed April 8, 1948 '9 Sheets-Sheet 9 v Patented July 29, 1952 UNITED STATES PATENT OFFICE 2,605,095 G'INE GOVERNOR MODIFIER' Clifford Muzzey, Lexington, Mass, and Howard Carson, Seattle, Wash., assign'o'rs to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application April 8, 1948, Serial No. 19,714

10 Claims. 1

This invention relates to an internal combustion turbine engine and propeller power plant for aircraft use.

An object of the invention is to provide a pro pelier pitch controller which is manually adjusted for various speeds and which will maintain the selected speed with the minimum of hunting. To accomplish this object, the invention includes means responsive to speed error, means responsive to the rate of change of speed error and blade pitch setting apparatus which is operated in response to the combined effects of said means whereby the rate of change of blade pitch is proportional to speed error and to the rate of change of speed error. Both said means contribute to the combined effect in proportions which are varied according to the blade pitch required for the selected speed. Concurrently with manual adjustment of the controller to maintain a selected speed, the controller is manually adjusted to obtain approximately the blade pitch required for the selected speed; and the blade pitch is accurately set automatically.

Further objects and advantages of the present invention will be apparent from the renewin description, reference being bad to the ace-om panying drawings, wherein a preferred embodiment of the present invention is clearly shown.

in the drawings v Figl is a view looking toward the propeller end of an internal combustion turbine engine -('en'gima' shaft in section) and shows means for mounting and driving the blade pitch controller and manually operated means for controlling blade pitch. 7 I Fig. 2 is a view in the direction of arrow 2 of Fig. i and shows the controller in the direction of arrow 2A'of Fig. 5. I

Figs.3 and 4 are sectional views respectively on lines 3--3 and 4-4 of Fig. 1.

Fig. 5 is a View of the controller in the direction of arrow 5 of Fig. 2.

Fig-6 is a sectional view on lines 6 6 of Figs. 2, 4 and 8. M

Fig. '7 is a sectional View on line 7 of Fig. 10. Fig. 8 is a sectional view on' lines 'B"8 of Figs. 5 m fi- Fig. 9 is asectional view on line 9-9 of Fig. 8. Fig. 1'0 is a sectional view onlines I*'*Ifl of Figs. and 6. Y Y

Fig. 11 is a view in the direction of arrow II of Fig.6, showing sections of certain parts on lineII*II-of Fig.1

FigJlZ is a s'ection'al' view on lines I'2'-"I2 of Figs. 2 and 11. Y

2 Fig. 13 is a sectional View on line I3" I3 of Fig.1 5. v

Fig. 14 is a sectional View on the line I4- l4 of Fig. 11. f v y 5 Fig. 15 is a sectional view on the line I5--'I5 Of Fig. 11.

Fig. 16 is a diagram of the controller.

Fig. 17 is a sectional View in perspective-of "a propeller assembly with which the controller is adapted to be used. 1

Fig. '18 is a fragmentary sectional view on line I8I8 of Fig. 17. g

Figs. 19, 20 and 21 are sectional views taken respectively on lines I9- I 9, 20 and 2I -2' I or Fig.18. V I

Fig. 22 is a fragmentary view in the direction of arrow 22 of Fig. 21.

Referring to Figs. 1 and 2, the engine fr'atn'e E supports a plate 25 and a sheet metal cover 26 attached by studs 21, nuts 28 and rivets 29 (Fig. 4) secure the cover 26 to the plate 25'. Controller C has a housing I00 which is attached to the plate 25 by screwsBil (Fig. 1). Engine shaft S (Fig. 4) drives a propeller assembly PH and a gear 3| meshing with an idle gear 32 which drives a gear IIil attached to the drive shaft H 'I of the controller C. u

A housing I08 is provided with a top cover IIH (Fig. 6) and a bottom cover I tzand with a thick walled partition I03 between thecovers. The spaces between the partition I03 and covers contain oil and are connected by passage I114 '(Fig. '7). Cover I 02 provides a. circular flange H15 which is received by a hole I06 in plate 25 (Fig. 4). Engine driven gear IIII drives shaft III journ'aled in a bearing sleeve H2 supported by the partition I03. The escape of oil from the reservoir IMb around the shaft III is prevented by a shaft seal of the ground surface type comprising a plate H3 with screws H4 attached to the cover I 02. Plate H3 retains a seal ring II5. Plate II 3 engaged by'the angularboss I I6 of a sleeve I I1 urged downwardly by a spring H8 which urges upwardly a washer H9 against the lower end of bearing sleeve I v I W The upper end of shaft III provides a gar I20 meshing with a gear IZ'I provided by plate I22 carrying a housing I23 which encloses a governor comprising weights I231 connected fsy strap hinges I25 with the plate I22; The weights I24 are connected by a flexible metal stirrup I25 which extends through notch-es ina plate I21 connected with a spool valve I28 having a land I29 and annular groove I30 connected by a cross passage I3I with a hole I32. The governor spring I35 is confined between a retainer I35 and a retainer I31 which bears against the outer race of a ball bearing I38 whose inner race bears against the plate I21. The upper end of valve I28 is threaded to receive a nut I39 which when tightened forces a washer I40 against the inner race of bearing I38 and the latter against the member I21 and it bears against washer I4I which engages a shoulder provided by the valve The hub of gear I2I is cup-shaped to receive a bearing bushing I44 which is journaled on a sleeve I45 received by a hole I46 in the partition I03 (Fig. 12). The sleeve I45 supports seal rings I41. The lower surface of the hub of gear I2I engages a bearing plate I48 which is supported by plate I49. Plate I48 is retained by a plate I50 with the screws I500. (Fig. 8) attached to the partition I03.

Between the sleeve I45 and the spool valve I23 there is located a sleeve valve i5I having an annular groove I52 with cross passages I53 connected to the interior of the sleeve. Groove I52 is in communication with cross passages I54 of sleeve I45 which are connected with annular groove I55. Sleeve valve I5I provides port I55 controlled by the land I29 of valve I23 and in communication with an annular groove 51 With cross passages I58 of sleeve I45 connected with annular groove I53. 7

The speed for which the governor is set is deter mined by the position of lever I55 (Figs. 5 and 8) which has a hub flange ISI of arcuate contour (Fig. 8) connected with and adapted to push on tangs I52 and I03 of discs I64 and I55 respectively attached to the end turns of a clutch spring I65. These tangs are engageable with the arcuate hub flange I61 of a hub I61a which a key I51?) connects with a shaft I68 journaled in a tube I69 integral with a plate I592) which screws I695: attach to the housing I (Fig. Shaft I68 is also journaled in a bushing I53a supported by the housing I00. There is a seal ring I581) between the shaft I58 and the tube I69 and a seal ring I590 between the tube I69 and the hub IGI of lever I50 and a seal IBIa between hub IBI and a bearing I in which the hub IfiI is journaled. The lever l50 can rotate the shaft I58 in either direction because the action of hub flange IBI is to unwind spring I56 and cause it to connect IBI with flange I61; but shaft I53 cannot back up and operate lever I50 in either direction because the tendency of flange I51 is to wind up the spring I66 and cause it to grip the tube I59.

Shaft I68 extends through a sleeve I12, shim washers I13 and the hub I14 of a lever I retained by a washer I15 and a nut I11 threadedly engages shaft I53. A key I28 connects the hub I14 with shaft I68. Lever I15 carries a pin I29 carrying a roller I80 for engaging a lever I8I which, through a cross pin I82, is connected with the spring retainer I35. Lever I8! has a bifurcated portion I83 connected by a pin I84 with a nut I85 threadedly engaged by a screw I55, the reduced lower end portion I81 of which is received by a socket I88 in the housing I03 and the upper end of which extends through a hole we 4 thereof from the flange I92 of plate I83. While the screw I is thus disengaged from the plate I93, the screw is turned in order to change the position of nut I85 relative to the screw I35. When the screw driver is elevated the screw I86 moves up to cause flange I8I to engage the flange I92, thereby holding the screw I86 against rotation. The adjustment of the position of nut I35 is factory set and the initial adjustment is left undisturbed. The control of spring I35 is eflected by means of the lever I 55.

The housing I0!) is filled with oil to about the level of the lower edge of the filler opening 250 which is closed by a plug 20!. The governor Weights I24 are submerged. Agitation of the oil by the weights is reduced by the cylindrical housing I23 which surrounds it.

The gear I2I drives a gear 205 connected with the drive 205 (Fig. 8) of a gear pump having a gear 201 meshing with a gear 258 (Fig. '7). A pipe 209 (Fig. 8) conducts oil from the housing to the pump inlet. The pump outlet is connected with a passage 2 II) in the partition I03 and connected with a bore 2 II which receives sleeve 2I2 retaining a seal ring 2I2a. Sleeve 2I2 provides a cylinder 2I3 which receives a piston 2I4 connected by its rod 2I5 with a notched disc 2 I5. A compression spring 2I1 is located between the sleeve 2I2 and the disc M5 and urges the latter upwardly so that the piston 2 I4 blocks the escape of oil from port 2 I8 in sleeve 2 I2 and to an annular groove 2I9 of the sleeve connected with a passage 220 which is connected with the oil reservoir. When the oil pressure increases to a certain amount, the pressure upon the shoulder of the piston valve 2 I4 becomes suflicient to overcome the spring 2I1 whereupon the piston 234 moves down to permit some oil to escape from the bore 2H) to the port 2I8. In this way the pump pressure is limited to a certain value. Sleeve 2 I2 is retained by a plate 22 I with screws 222 attached to the partition I83. Plate 22! has a hole 223 for the escape of oil which might otherwise be trapped in the lower end of cylinder 2I3.

Partition I03 has a bore 230 which receives a sleeve 23I retaining seal rings 232. Sleeve 23I is retained by a plate 233 which a screw 234 (Fig. 8) attaches to the partition I03. Sleeve 23I receives a spool valve 235 having a land 236 and a guide flange 231. Sleeve 23I has an annular groove 238 connected by passages 239 with the interior of the sleeve and thence to the space between the land 235 and the flange 231. The land 236 controls port 240 connected with annular groove 24I of sleeve 23I. If valve 235 moves up oil can escape from the ports 240 and return to the reservoir through the lower end of the sleeve 23I. If valve 235 moves down the ports 239 and 240 will be connected. Position of valve 235 is controlled by a plate 242 which carries a screw 243 having a pad 244 against which the valve 235 is urged by a compression spring 245 bearing against the plug 246 in the sleeve 23I and against the flange 231 of valve 235. The screw 243 is retained in the desired position of adjustment by lock nut 241. A stud 250 threaded into the partition I03 passes through a hole in the plate 242 and is surrounded by a spring 2'5I which presses against the plate 242 and against a washer 252 retained by a nut 253 threadedly engaging the stud 250. The spring25l presses the plate 242 against a pin 254 (Fig. 10) and. against an adjustable pin 255 which can be inserted into one of a series of holes 256 in the partition I03. The location 5 of pin 255 determines the leverage of plate 242 relative to valve 235 which the screw 243 actuates, said leverage being the distance from the axis of screw 243 to a line joining the axes of pins 254 and 255.

A coil spring 260 (Fig. 10) received by socket 26I inthe partition I03 surrounds a spring retainer provided by a stud 262 attached to plate 242. As viewed in Fig. 10, this spring 260 pushes the upper portion of plate 242 away from the partition I03 and toward the observer. This causes the plate 242 to engage a disc 263 (Figs. 6 and 10). Sleeve valve I'5I is urged against plate 242 by leaf spring 264 which is attached to the plate. This spring extends into a notch 265 in the valve I5I, said notch being cut into the bore in the valve so that oil can escape from the interior thereof through the oil reservoir. In Fig. 10, the point of engagement of plate 242 with the valve I5I is designated by the dot 266. The leverage of valve I5I with respect to the plate 242 is the perpendicular distance from the dot 266 to a line passing through the points of contact of plate 242 with the pins 254 and 255.

The disc 263 has a slot 210 which receives pin 21I which is carried by tube 213 guided by a bushing 214 which screws 215 attach to the housing I00. Tube 213 carries a seal ring 216 and the bushing 214 a seal ring 211. The bushing 214 provides diametrically opposite slot 218 and 219, the former receiving flats 280 provided by a flange of pin 21I and the latter receiving the pin itself. Thus the pin 2H and the tube 213 are non-rotatable. The left end of tube 213 is guided by a bushing 282 retaining a seal ring 283 and attached to the-housing by screws 284. A spring 285 within the tube 213 bears against the tube and the bushing in order to move the tube toward the right, thereby causing the roller 286 journaled on a cross pin 2B1 supported by the tube to engage a cam 290 pivotally supported by a screw 29I fixed to a bracket 292 (Fig. 6) which screws 293 attach to the housing. Cam 290 has a lever arm 294 carrying a stud 295 pivotally supporting a roller 295a received by the radial slot 296 of a lever 291. Lever 291 has a hub 298 (Fig. 5) which a key 299 connects with a. shaft 300 which is operatively connected with a'lever 30I retained by nut 302 threaded on the shaft. Shaft 300 is journaled in the tubular part 303 of the housing I and is connected at its upper end by a key 304 with a hub 305 of a lever 306, said hub being retained by a nut 308 threaded on the upper end of shaft 300. Lever 306 has a lug 309 for a purpose to be described.

Lever 306 is received by the bifurcations 3I0 (Fig. of rod 3 supported for a sliding movement by cylinder casting 3I2 which screws 3I3 attach to the housing I00. Rod 3II carries pins 3I'5 and 3I6, the latter supporting a roller 3I1.

Lug 309 of lever 306 (Fig. 8) is engaged by the head 320 of a screw 32I integral with a rod 322 which extends through a cylinder 323 which screws 324 attach to the housing I00. A spring 325 compressed between the end of the cylinder and a nut 326 threaded on screw 32I urges the lever 306 counterclockwise (Fig. 8) and clockwise (Fig. 10). Lock nut 321 retains nut 326 in the desired position of adjustment.

Spring 325 urges rod 3I I to the right in Fig. 5 against a lever 339'pivotally connected by pin 331 with a piston rod 332 of a piston 333 within a cylinder 334 in the casting 3I2. At its right end (Fig. 10) the cylinder 334 is connected by a passage 335 in casting 3I2 with a passage 336 in the housing I00. The left end of the cylinder 334 is connected by passage 331, annular groove 333 in cylinder 334 by passage 339 in the casting 3I2 with a passage 340 in housing I00. Any oil seeping past the piston rod 332 is received by an annular groove 34I connected by passage 342 connected with annular groove 343 of the cylinder 334, connected with passage 344 in casting 3I2 connected with passage 345 in housing I00 which leads to drain. The cylinder 334 is secured to the casting 3I2 by screw 346. Seal rings 341, 348 and 349 are provided as shown to prevent leakage of oil around the cylinder 334 and the piston rod 332 and the casting 3I2; and seal rings 350, 35I and 352 are provided as shown to prevent leakage of oil at the joints between the casting 3I2 and the housing I00.

The lever 330 is straddled by the bifurcations of lever 355 which a key 356 (Fig. 8) attaches to the shaft I68. A nut 358, threaded on the shaft, retains the lever 355. Pins 359 (Fig. 5), carried by the lever 355, provide journals for rollers 360 and 36I which engage a cam surface 362 provided by lever 330. In a certain range of operation, the surface 362 is engaged solely by roller 360 and in another range, it is engaged solely by roller 36 I When the lever I60 is moved clockwise (Fig. 5) from low speed position toward the higher speed position, lever 330 moves counterclockwise about its pivot 33I to cause the rod 3I I to move toward the left or toward the right in Fig. 10. When the lever I60 is in position for selecting the lowest blade angle, the piston 333will be in its leftmost position in Fig. 10 which would be rightmost in Fig. 5. Therefore, the rod 3I I will be at its rightmost position in Fig. 5 and at its leftmost position in Fig. 10. Spring 325, acting through. rod 3I I, tends to maintain the piston 333 in the position referred to.

Considering the servo piston rod 332 to be fixed for the moment, the actuator I 60 calls for a blade anglecorresponding approximately to a certain power requirement by moving the rod 3H and hence the lever 30I. The piston rod 332 is caused to move in order to effect an accurate setting of the blade-angle to maintain the speed for which the governor is set. This rod 332 is under control directly by the differential of pressures acting on opposite sides of piston 333. As will be explained later, the pump maintains a pressure on the left side of the piston and the pressure on the right side of the piston is under control by valve 235 and by a stabilizer which includes a cylinder 310 received within a recess 31I of the housing and sealed therein by a ring 312. At the top the cylinder is closed by a cap 313 having a passage 314 connected by passage 315 with the annular groove I59 of the sleeve I45. The lower end of cylinder 310 is connected by passages 380 and 336 with the annular groove 24I of sleeve 23I in which valve 235 is located and with the head end of cylinder 334. The pump is connected by passages 339 and 340 with the rod end of cylinder 334. Cylinder 310 receives a piston 390 connected by a rod 39I and a pin 392. with a lever 393 which is rigidly connected with the disc 263. Therefore the piston 390 controls the position of the plate 242 which controls the position of sleeve valve I5I and the position of the spool valve 235. Passage 38I connects the annular groove I 55 of sleeve I45 (Fig. 6) with the annular groove 238 of sleeve 23I (Fig. 7). Passage 339 (Figs. 11' and 7) is connected with passage 2I0 which connects the pump with the pressure control valve 2 I 5 and with a filter chamber 400 (Fig.

.6) containing a filter40I, the interior of which is connected by passage 402 with groove I55 of sleeve I45. Drain passage 345 (Figs. and 11), is connected with passage 3 80.

Referring to Fig. 16, the rod M represents a manual operated member operated by the pilot. It moves a fuel control lever F and lever I60 (shown in two places in Fig. 16) which through lever I75 sets the governor spring I35, thereby selecting the speed which the controller is to maintain by control of blade angle through lever 30!. Lever I50 also directly moves the lever 36! through the mechanism comprising lever 355, one of the rollers 360, 36!, differential lever 330, rod 3II, roller 3I'I, lever 309 and shaft 305. Thus for any power demand indicated by scale N, there is a fuel setting and a speed setting and a blade angle setting indicated by scale B adjacent lever 30 I. If the blade angle set by rod Mdoesnot correspond with the speed setting of the governor, the controller makes the correction.

For any speed setting of the governor, the flyweights I24 have the same equilibrium position relative to their axis of rotation. Valve I28 has an equilibrium position blocking port I56 of sleeve valve I5!. Piston 390 is in equilibrium position shown maintaining valve I5! in equilibrium position through the connection provided by lever 393 and plate 242 which spring 260 urges against the disc 263 while spring 264 urges the valve I5! against the plate 242. If the blade setting efiected by rod M (acting through lever 355, a roller 36!) or 36!, lever 33!), rod 3! I, lever 306, shaft 300 and lever 30!) does not so control the engine that its speed corresponds with that for which the governor is set, the governor will sense the difference in speed or speed error, and move the valve I28. Any speed error results in movement of piston 390. The greater the error, the greater will be the displacement of piston 350 because it moves the valve I5! as a follow-up to bring its port I56 into alignment with the land I29 of valve I23. The rate of movement of the piston 390 is therefore proportional to the rate of change of speed error.

If the speed error is positive, port I56 is opened to drain through the bottom of valve I5! and pressure above piston 399 is relieved and piston 390 is moved up by oil flowing into the lower end of cylinder 310 through passage 380 connected by passage 336 with the right end of cylinder 334, said flow being caused by right movement of piston 333 under pump pressure on its left side. Because the rate of movement of piston 390 isproportional to the rate of change of speed error, the flow of oil through passage 380 to the cylinder 310 is proportional to the rate of change of speed error.

Since the displacement of piston 390 is proportional to the amount of speed error, the displacement of valve 235 (which is actuated by piston 390 through lever 353, disc 263 and plate 242, fulcrumed at 255), is proportional to speed error. As valve land 233 is displaced upwardly, oil flows from the right end of cylinder 334 through passage 335 and port 240 to drain at a rate proportional to speed error.

Consequently oil flows from the right end of cylinder 334 at a rate which is equal to the combined rates of flow through passage 335 to drain and through passage 380 to cylinder 310. The piston 333 moves right at a rate proportional to speed error and the rate of change of speed error and a corresponding rate of movement is imparted to lever 30! through the mechanism which includes lever 33!! fulcrumed on a roller'360 or 36!, rod 3! I, lever 306 and shaft 300., Speed error is eliminated promptly without hunting by increase of blade angle since the controller is responsive to the amount of speed error and to the rate of change of speed error. When speed error has been eliminated, the piston 390 and the valves I28, I5! and 235 are in equilibrium position as shown in Fig. 16.

If the speed error is negative, the action is reversed. Valve !28 is lowered and oil is forced by the pump into the top of cylinder 310 and piston 390 moves down and valve 235 moves down to connect the pump with passage 336. Oil flows into the right end of cylinder 334 at a rate proportional to displacement of valve 235 downwardly which is proportional to speed error and at a rate proportional to the rate of flow out of the lower end of cylinder 310 through passage 380 which is at the rate of downward movement of piston 390 which is proportional to the rate of change of speed error. The effective area on the right face of piston 333 being greater than the left face area, the piston 333 is forced left at a rate proportional to the amount of speed error and to the rate of change of speed error. As piston 333 moves right, lever 330 moves clockwise about its fulcrum (one of the rollers 360, 36!), rod 3!! 'moves left under the action of spring 325 which rotates lever 306, shaft 300 and lever 30! clockwise to decrease the blade angle so that engine speed can increase.

When a sudden increase of power by increase of fuel and speed is demanded, control lever IE0 is moved rapidly counterclockwise (Fig. 16) to increase suddenly the compression of governor spring I with theresult that valve I29'is quickly moved below its equilibrium position which causes valves I29 to call suddenly for lower blade angle. There would be a false or over acceleration of the engine during the interim between the demand for a certain increase in speed and the return of valve I5! to equilibrium position were it not for the fact lever I60, acting through rod 3! I, lever 306, shaft 300 and lever 30!, demands a higher blade angle. Conversely, when lever I is moved suddenly clockwise in response to demand for less speed and fuel and the compression of spring I35 is suddenly reduced, valve I29 moves up suddenly and calls for a high blade angle while lever I50, acting through rod 3! I, lever 356, shaft 300 and lever 30!, demands a lower blade angle. Therefore, satisfactory governing action is obtained whether the movement of lever I5!! is fast or slow.

The law of action of the controller is represented by czlcm-i-kmi in which ,8 is rate of change of blade angle. n is the amount of speed error, it is the rate of change of speed error, 701 is the sensitivity constant of the governor and k2 is the sensitivity constant of the acceleration responsive mechanism which includes'the stabilizer piston 390. The constant k2 is determined by the distance between the center line of pin 21! and the center line of valve I5! relative to the distance between pin 392 and pin 2'! I This relation is varied by changing the position of pin Fig. 10 shows that pin 255 may be placed in one of a series a holes 256 in partition I03. Fig. l6 shows the pin 255 supported by a bracket 2557' with a screw 2557c, passing through a slot in the bracket, attached to a support 2551. By movk2+ /2Ik1, I being a constant, but the primary effect of change of k1 isto change the basic time constant of the control. A change in the position of pin 211 causes a pure change in stability without altering the time constant.

Analysis of the aerodynamic properties of the propeller indicates that different quantities of control damping (represented by R12) are required for difierent blade angles. The demand for increased engine power which is satisfied by increase of burner fuel and increase of speed results in higher blade angle by means of which the power is absorbed. As blade angle increases, the slope of the curve of aerodynamic torque versus rotational speed increases. Since the slope of this curve represents the natural aerodynamic damping which the propeller contributes to the system, the constant k2 can be decreased with increased power demand so that the total damping (control damping plus aerodynamic damping) will remain approximately constant. As shown in Fig. 16, as lever 301 moves up to increase blade angle, cam 290 is moved counterclockwise to permit spring 285 to move the fulcrum pin 211 to the right, thereby decreasing the ratio of the leverage of piston 390 with respect to pin 2'11 to the leverage of valve 151 with respect to pin 2'11. Because this leverage ratio decreases with increase of blade angle, the acceleration sensitivity coefficient 762 decreases. Cam 290 is shaped to effect decrease of 762, with increase of blade angle according to a schedule suitable for the particular turbinepropeller power plant.

In the lower power range contact between lever 355 and lever 330 is made through roller 350 acting on cam surface 362. In the high power range, roller 361 engages cam 362 and takes over control to render the controller less effective under high power conditions since the aerodynamics of blade angle change under these conditions provide greater eifect in the governing function.

As viewed in Fig. 1, lever 29'! is urged clockwise by spring 325 (Fig. 8). spring 325, a spring 410 connecting lever 301 with a bracket 411 attached to plate 25 can be substituted. A link 412 connects lever 301 with arm 541a of a ring gear 541 which is a part of the propeller hub assembly PH which will be described later. Gear 541 has an arm 541b carrying apin 4 I 3 received by a slot 414 in a plate 415 attached to a tube 416 which telescopically receives a Bowden wire tube 41! which is fixed by a clip 418 to bracket 411. Tube 415 is guided by a bracket 419 attached to plate 25 and by the tube 411. Tube 416 is connected with a Bowden wire (not shown) within the tube 411. In. case of failure of the controller, the rod can be manually operated to control blade angle. Slot 414 permits automatic operation of gear 541 without shifting plate 414 from its low blade angle position.

The propeller assembly with which the present invention is adapted to be used, may be, for example, like those disclosed in the patents to Blanchard and MacNeil Nos. 2,307,101 and 2,307,- 102, issued January 5, 1943. Fig. 17 shows somewhat diagrammatically a propeller hub and torque unit assembly of the type disclosed in I Instead of using these patents. From the engine frame E there extends an engine driven shaft 501 which sup.- ports and drives a propeller hub 502 which supports an accumulator 503 containing a piston 504 movable toward the right from the position shown under the action of compressed gas forced into the accumulator through a check valve 505. The space, between the piston 504 and the fixed wall 505 of the accumulator, receives oil under pressure which forces piston 504 toward the left further to compress the gas to the left of the piston, thereby maintaining a supply of oil under pressure for the purpose of feathering and unfeathering the propeller blades. Duct 501, through which oil flows into the accumulator, is controlled by a valve to be described.

The hub 502 supports aplurality of blades 510, each having its root journaled 'in bearings 511. Each blade is rotated about its root axis by separate torque unit comprising a cylinder 512' attached to a blade root and having its upper end closed by cap 513 rotatably supported at its lower end by a bearing 514. Cylinder 512 cooperates with a piston 515 having external helical splines 516 cooperating with internal helical splines 511 of the cylinder 512 and having internal helical splines cooperating with external helical splines 518 of a relatively fixed member 519 supported by' the hub 502.. Pipes 520 and 521 lead'respec 'tively to the inner and outer ends of the cylinder 5'12 and are connected in a manner to be'dee scribed with a distributing valve. The'spiral splines are so constructed that inward movement of the piston 515 effects rotation of the cylinders 512 (clockwise looking outwardly) for the pitch increasing function; and outward movement of the piston 515 effects rotation of the cylinders 512 in opposite direction for the pitch decreasing function. The cylinders 512 are each connected with a bevel gear segment 522, each meshing with a master gear 523 supported by a bearing 524 carried by the hub 502, thereby equalizing the pitch changing movements of the blades.

The hub 502 supports a plate 530- which,- as shown in Fig. 19, is secured by tubular nut 531. The plate 530 and its cover 532 (Fig. 17 provides a reservoir for hydraulic fluid. The engine shaft 501 is surrounded by a non-rotatable tube 533 concentric with the shaft and with the nut 531' (Fig. 19). (Fig. 17) received by a notch between brackets 535 attached to engine frame E. The plate 530 and its cover 532 provide bearings which maintain the concentricity of the tube 533, one of these bearings being shown at 536 in Fig. 19. Each bearing has a seal such as 5131. Tube 533 provides an annular flange 538 which supports a plurality of shafts 539, each driven by a pinion 540 meshing with a ring gear 541 rotatably supportedin any suitable manner by the sleeve 533. Ring gear 541 is provided with a handle or lever 5410. which may be operated by a setting device which is under direct manual control or by the controller C.

Rotation of gear 541 by lever 541a or lever 541b effects rotary movements of shafts 539 for the purpose of obtaining blade pitch change. Each shaft 539 provides a screw 545 threaded into a grooved ring 546 slidably along the tube 533. Ring 546 receives a shoe 541 (Fig. 18) attached to a rod 548 guided for movement parallel to the shaft 501 by the plate 530. Shoe 541 connected by screw 549 with a bar 550'having a slot 551 which receives a shoe 552 provided by a pin 553 which swivels in a carriage 554'supported by roll-.

Tube 533 is provided with a tang 534 11 ers 555 slidable in ways provided by channel brackets 556 attached by screws 55? to a valve body 558 attached by screws 559 to the plate 533. The'valve body 558 is part of a distributing valve unit 550 comprising a valve 55! slidable in a valve sleeve 552 having ports 553, 555 and 55? connected by annular grooves 554, 556 and 555m 'spectively with holes 559, 510 and respectively. l-Iole 5'58 is connected in a manner to be describedwith a pressure pump. Hole 559 is connected with passages 52 I and hole 57! is connected with passages 52%). .The position of valve 5'5! is determined by the position of carriages 554 which carries a roller 512 engageable with a lever 513 pivotally supported by pin 514 carried by a screw 515 attached to the valve body 553. Lever 513 is provided with a notch 515 receiving a pin 51'! attached to the valve 55!. Since centrifugal force acts upon the valve 55! as indicated by arrow 551a, Fig 19, the lever 5'13 remains in engagement with the roller 552 while the propeller hub is rotated. Hence, no spring is required to hold the lever 513 against the roller 512. In the disclosed apparatus, when ring gear 54! is rotated counterclockwise in Fig. 17 or clockwise in Fig. 1, an increase of blade angle is effected. Pinions 555 and shafts. 539 rotate counterclockwise thereby causing the grooved ring 545 to move toward theleft, thereby moving the carriage 554 toward the left. As roller 572 moves toward the left, centrifugal force causes the valve 55! to move upwardly, thereby connecting holes 515 and 559 which causes pres: sure fluid to flow through pipes 52! in order to force the piston 5l5 inwardly whereby. blade pitch is increased. While the blades 5!!! are being rotated about their root axes in the direction of pitch increase, the valve 56! is being returned to a balanced position, closing ports 558 and 55'! at which position the valve arrives when the demand for pitch increase has been satisfied. In order to accomplish this, the master bevel gear 523 is connectedwith' a gear 550 (Fig. 21) which is retained by a plate 58! attached to the hub 502 and which meshes with a gear 582 pivotally supported by a screw 583 attached to a plate 584 supported by hub 552. Gear 582 meshes with gear 585 attached to a shaft 585 having a bearing and a boss 58'! integral with the plate 584. Shaft 585 is connected with a coupling disc 588 connected by a screw 589 with a coupling disc 590 attached to a shaft 59! journaled in a bearing 592' carried by the plate 535 and retained by a nut 593 threaded on the bearing 592 as shown in Fig. 21. Shaft 55! is provided with a helical groove 595 which receives a ball 596 carried by a member 59'! which serves as a nut and travels along the helical or screw-threaded groove 595. Nut 59'! provides a stud 593 passing through a slot 599 in bar 553 and retained by a nut 600. The back lash in the gears 582 and 555 is taken up by spring 60! having one end received by a notch 552 .in the boss 58'! and the other end received by notch 503 in the hub of the coupling. disc 588. The spring 55! is initially wound .up in order to spring-load the gears 585, 582 and 585. Coupling screw 535 passes through an elongated arcuate hole 590a in the disc 595, thereby providing for angular adjustment between the coupling discs 588 and 59B.

When carriage 554 isin the position shown in Fig. 19 and in full section lines (Fig. 20), the valve 56! is in neutral position blocking ports 563 and 55! so that the torque units will not operate. One set of conditions which places valve 55! in neutral position, is that which exists when screw 549 and stud 598 are'located as shown in Fig. 20. These are the conditions for minimum positive or maximum negative pitch. To decrease pitch negatively and -increase pitch positively, gear 54! is rotated counterclockwise thereby causing ring 546 and carriage 54'! to move left from the position shown in Fig. 18. The demand for pitch increase, posi-.- tively, may be such as to place screw 549 in position 549 and bar 553m position 555' and carriage 554 in position 554 (Fig. 20) This will effect blade angle increase, positively, in the manner described. During blade angle increase, the master gear 523 rotates counterclockwise as indicated by arrow 5230. in Fig. 1'? or clockwise in Fig. 22, as indicated by arrow 523D. Therefore the shaft 586 will rotate clockwise in Fig. 22. thereby causing the screw 535 to rotate counterclockwise as indicated by arrow 595a when viewed from the direction of arrow 5951) (Fig. 21'). Therefore, while the blades are being rotated to increase pitch, the nut 59'! will be moving down in Figs. 20 and 21 thereby carrying the stud 595 to the position 598" which causes the carriage 554 to be brought back into position shown in full lines in Fig. 20, thereby returning the valve 56! in balanced position. If the movement of ring 545 had been such as to cause the screw 549 to move to 545", the carriage 554 would have been moved further than 554, thereby demand: ing a greater blade angle change which would cause the stud 598 to moveto 558". before the valve 555 is returned to balanced position. It is therefore apparent that for every position of the ring 545 there is a definite blade angle; Consequently, for every position of lever saw, there is a definite blade angle position. The mechanism shown provides for adjustment of blade angle in a range of approximately The flange 538 of sleeve 533 (Fig. 1'7) provides a stationary gear 6H] meshing with a gear 6!! which drives a pump PP while the propeller hub is rotating. The outlet of pipe p of pump PP is connected with the passage 5'! of the distributing valve 560. Pipe 1:) is connectedby pipe pi with a pressure control unit PC connected by pipe pa with an accumulator control valve unit AV. The. pressure control unit PC comprises a valve rod 535 having a dashpot head 53! received by acylinder 532 connected with pipe 101 and urged outwardly by centrifugal force acting in the direction of arrow 533 and by spring 534 in opposition to fluid pressure acting upon the lower surface (Fig. 17) of a piston valve 335 received by a cylinder 335 and controlling a relief port 631. The inner end of cylinder 6351s connected by pipe 538 with pipe 52! as shown also. Valve 635, being responsive to centrifugal force, causes the pressure in line p to increase as speed increases and this pressure is increased also when cylinder 633 receives pressure from the pipe 52! which is under pressure when there is a demand for pitch increase.

The unit PC includes also a minimum pressure control valve provided by a rod 640 having lands 64! and 542 for controlling the connection between port 63! and a discharge port 643. The rod 649 has a dashpot head 544 engaged by a spring 645 located in a cylinder 646 connected with cylinder 552. The force :of spring 545 is opposed by the fluid pressure acting upon the under side of valve land 64! (Fig. 1'7). The pressure available in pipe p will be limited to a minimum value by movement of rod 645 to a 503 to'pip'e n.

ring 546 is moved to the extreme left to cause 13 position for connecting the ports till and 643, valve 635 having opened port 631. Up to a certain rotative speed of the hub, the pressure is limited to a minimum value in order that the accumulator will be fully charged within a short time even while the engine is operating at low speed. This minimum pressure is sufficient for the pitch-decreasing function of the torque units. As propeller speed increases, valve 635, being under control by centrifugal force, requires greater line pressure to cause the opening of the port 631. Therefore the pressure increases in pipe p above the minimum in order to make available the pressure required for the pitchincreasing function which requires greater pressure with increase of speed.

While rod 640 of unit PC is shown parallel with rod 630 which is under the action of centrifugal force, it will be understood that rod 640 is not controlled by centrifugal force but is actually located at right angles to rod 630; The units PC and AV are fully described in the cop'ending, application of David A. Richardson, Serial No. 613,563, filed August 30, 1945.

- For the understanding of the present invention, it is suflicient to state that the accumulator control valve unit AV has a check valve 659 which normally blocks flow from the accumulator When feathering is required,

a roller 65! (carried by a shoe 652 received in thegroove of ring 546) to engage cam 653 on alever 654 and to effect downward movement of said lever and of a rod 655, thereby opening the check valve 650. Pressure oil then flows from the accumulator to underside (in Fig. 17) of a piston 656, thereby effecting the opening ofa valve 651 so that the accumulator may discharge to pipe 101 through a by-pass around the checkvalve. During this discharge the valve 651 is held open by oil pressure against the underside (in Fig. 17) of a piston 658. As feathering is" completed, the pressure differential between the pressure in pipe 101. and the pressure against the under-side of piston 658 decreases and spring 659 closes valve 651. Cam 653" having been momentarily contacted by roller 651' during movement of ring 546 to the extreme left, check valve recloses. Therefore discharge of the accumulator is prevented until it is desired to use accumulator pressure to assist in the unfeat-h'ering operation. This is effected by right movement (in Fig. 17) of ring 546 which efiects momentary opening of check valve 650; and'discharge of the accumulator into pipes pi and ptakes place.

'If feathering is required on any type of engineropeller power plant with which the present controller is used, feathering would be controlled engine having means for increasing or decreasing its lcadIcoxhprising a movable member for con trolling the engine loading means, a speed re sponsive device driven by the engine, manually "14 operable engine power selecting means for'a'd justin'g the device to control for a selected speed and. for moving the member to obtain engine loading corresponding to th'eselec'ted speed, and means under control by the device foradjusting the member independently of the manual adjustment by the powerselecting'means to change the engine loading in case engine speed deviates from selected speed. I

2. Engine control apparatus for use with an engine having means for increasing or decreasing its load comprising a movable member for controlling the engine loading meansfa mechanism for moving said member including a dir ferential lever, a speed responsive device driven by the engine, manually operable engine power selecting means for adjusting the device't'o control for a selected speed and for moving the lever to move the member to obtain engine loading corresponding to a selected speed, and means under control by the device for moving the lever independently of the manual adjustment by the power selecting means to adjust the member to change the engine loading in case engine speed deviates from selected speed.

3. Engine control apparatus for use with an engine having means for increasing or decreasing its load comprising a movable member for controlling the engine loading means, a fluid pressure source, a fluid operated servo having a movable member operated by said, source, a differential lever operatively connected with the servo member, a speed responsive device. driven by the engine, manually operable enginepower selecting meansfor adjusting the device to control for a selected speed and having a part connected with the lever to move it independently of the servo member, a mechanism'for transmitting movement from the lever to the firstmemher to obtain engine loading corresponding to the selected speed, and means under control by the device for controlling movement of the servo member to obtain movement of the lever-and first member independently of the manual means to change the engine loading in case engine'sp'eed deviates from selected speed.

4. Engine control apparatus for use with'an engine having means for increasing or decreasing its load comprising a movable member for controlling the engine loading means, a-fiuid pressure source, a fluid operated servo comprising a cylinder, a piston therein and a rod connected with the piston and passing through an end of the cylinder, a duct connecting the pressure source with the rod end of the cylinder, 2; second duct connected with the other-end of the cylinder, a differential lever connected with the rod, a speed responsive device driven by the engine, manually operable engine powerseie'cting means for adjusting the device to control for a selected speed and having a part operatively connected with'the lever to moveit independently of the piston; a mechanism for transmitting movement from the lever to the first mberto' obtain engine loading corresponding" ti) the selected speed, and means under contriil by the device and operating in case engine si ieedd'e viates from selected speed to: centror new of fluid into or out of the second-duct in order to move said lever and member independently 61" the manual means to change theengine reading; 5. Engine contra a paratus or use withan engine having means for increasing or decrees ing its load comprising a movable member for controlling the engine loading means; d iiuid,

15 pressure source, a fluid operated servo comprising a cylinder, a piston therein and a rod connected with the piston and passing through an end of the cylinder, a duct connecting the pressure source with the rod end of the cylinder, a second duct connected with the other end of the cylinder, a difierential lever connected with the rod, a speed responsive device driven by the engine, manually operable engine power selecting means for adjusting the device to control for a selected speed and having a part operatively con- 7 nected with the lever to move it independently of the piston, a mechanism for transmitting movement'from the lever to the first member to obtain engine loading corresponding to the selected speed, means under control by the device for effecting fluid flow into or out of the second duct at a rate equal to a factor (101) timesspeed error plus a factor (k2) times rate of change of speed error, and means responsive to movement of said member for varying the factor k2.

6. Engine control apparatus for use with an engine having means for increasing or decreasing its load comprising a movable member ior controlling the engine loading means, and engine operated flyweight governor, a spring opposing separation of the weights by centrifugal force, a fluid pressure source, a stabilizer cylinder, a piston therein, a lever connected with the piston and having an adjustable fulcrum, a fluid pressure source, valve-means normally blocking fluid flow into one end of the stabilizer cylinder from the source or out therefrom to drain when engine'speed equals that for whichthe governor is adjusted, said valve-means comprising a valve operated by the governor and a follow-up valve operated by the lever whereby the stabilizer pi'ston is displaced from equilibrium position an amount proportional to speed error and at a rate proportional to the rate of change in speed error, a duct connected with the other end of the stabilizer cylinder in which fiuid'will flow at the rate determined by the rate of movement of the stabilizer piston, a servo-motor havinga cylinder, a piston and a piston rod outstanding through one end of the cylinder, a second duct connected with the other end of the cylinder and with the first duct, a valve operated by the lever for connecting the second duct with the source or with drain when speed error exists, manually operable engine power selecting means for adjusting the governor spring, mechanism actuated jointly by the; servo-piston and said manually operated meansfor moving the member and means responsive to movement of the member foradjustingthe fulcrum of the lever.

7. Engine control apparatus for use, with an enginehaving means for increasing or decreasing its load comprising a movable member for controlling the engine loading means, an engine operated flyweight governor, a spring opposing separation of the weights by centrifugal force,a fluid pressuresource, a stabilizercylinder, a piston therein, a lever connected with the piston and having an adjustable fulcrum, a fluid pressure source, valve-means normally blocking fluid flow into one end of the stabilizer cylinder from the sourceor out therefrom to drain when enginespeed equals that for which the governor isadjusted, said valve-means comprising a valve operated by the; governor and a follow-up valve operated by the lever whereby the stabilizer piston is displaced from equilibrium position an amount proportional to speederror and at a rate proportional to the rate of change in speed error, a duct connected with the other endofthe stabilizer cylinder in which fluid will flow at the rate determined by the rate of movement of the stabilizer piston, a servo-motor having a cylinder, a piston and a piston rod extending through one end of the cylinder, the piston rod end of the cylinder being connected with the source, a second duct connected with the other end of the cylinder and with the first duct, a valvefor connecting the second duct with the source or with drain when speed .error exists, a second lever operatively connected with said valve and the first lever, means for adjusting thefulcrum of the second lever, manually operable engine power selecting means for adjusting the governor spring, mechanism actuated jointly by the servopiston and said manually operated means for moving the member. j

'8. Engine control apparatus for use with, an

engine having means forincreasing or decreas ing its load comprising a movable member for controlling the engine loading means, a differential lever operatively connected with the member, a first actuator connected with'the lever, a second lever actuator having two parts which sequentially engage portions of the lever at different distances from the first actuator as the second actuator is moved, a speed responsive device driven by the engine, means under control by said device for moving the first actuator to operate the lever and to adjust the member in case engine speed deviates from the speed for which the deviceis set, manually operable engine power selecting means for adjusting the device to maintain a selected speed and for operating the second actuator. v

9. Engine control apparatus for use with an engine having means for increasing ordecreasing its load comprising a movable member for controlling the engine loading means, a first actuator, a differential lever connected at one end with the first actuator and providing a surface at its other end portion for engagement by a second actuator, a mechanism, operatively connecting an intermediate portion of the lever with the member, a second actuator comprising a lever and two parts carried thereby and movable sequentially into contact with portions of the differential lever surface which are located at different distances from the first-actuator,- a speed responsive device driven by the engine, means under control by said device for moving the first actuator to operate the lever and to adjust the memberv in case engine speed deviates from the speed for which the device is set,;and manually operable meansfor setting the speed which the device is to maintain and for operating the second actuator to obtain engine loading corresponding to the speed setting. 10. Engine control apparatus for use with an engine having means for increasing or decreasing its load comprising a movable member for controlling the engine loading means, an hydraulic servomcomprising .a cylinder having a head end and a rod end, a piston and'a piston rod extending through the rod end of the cylinder a differential lever'connected at one end with the piston rod, a manually operated actuator operativelyconnected with the differential lever,.a mechanism for transmitting 'tothe member movements of the differential lever effected by the piston rod and by, manually operated actuator, a flyweight governor operated by the engine having a spring opposing movement of the,

17 weights by centrifugal force, manually operable engine power selecting means for adjusting the spring to select the speed which the governor is set to maintain and for moving the manually operated actuator to obtain through adjustment of said member engine loading corresponding to the speed setting of the governor, first and second valve guides having inlet and outlet ports, a fluid pressure source connected with said inlet ports and with the rod end of the servo cylinder, a stabilizer cylinder, a piston therein, a duct connecting the outlet port of the first guide with one end of the stabilizer cylinder, ducts connecting the head of the servo-cylinder with the other end of the stabilizer cylinder and with the outlet port of the second valve guide, a sleeve valve in the first valve guide and having inlet and outlet ports connected respectively with the inlet and outlet ports of its valve guide and having a passage to drain, a spool valve located within the sleeve valve and operated by the governor when speed error exists either to connect the inlet and outlet ports of the sleeve valve or to block the inlet port and to connect the outlet port with drain, means for effecting movement of the sleeve valve in response to movement of the stabilizer piston, a valve in the second valve guide operable when speed error exists either to connect the inlet and outlet ports of its valve guide or to block the inlet port and connect the outlet port with drain, and means for effecting operation of the last mentioned valve in response to movement of the sleeve valve.

CLIFFORD L. MUZZEY.

HOWARD CARSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,701,274 Rabbidge Feb. 5, 1929 2,039,495 Schlosser May 5, 1936 2,281,222 Baierlein Apr. 28, 1942 2,361,954 Martin Nov. 7, 1944 2,398,713 Martin Apr. 16, 1946 2,421,873 Forsythe June 10, 1947 2,454,914 De Marco Nov. 30, 1948 2,466,775 Martin Apr. 12, 1949 FOREIGN PATENTS Number Country Date 89,219 Sweden May 4, 1937 212,020 Switzerland Jan. 16, 1941 

